RESUMO
Capsicum baccatum L. is one of the five Capsicum domesticated species and has multiple uses in the food, pharmaceutical and cosmetic industries. This species is also a valuable source of genes for chili pepper breeding, especially genes for disease resistance and fruit quality. However, knowledge of the genetic structure of C. baccatum is limited. A reference map for C. baccatum (2n = 2x = 24) based on 42 microsatellite, 85 inter-simple sequence repeat, and 56 random amplified polymorphic DNA markers was constructed using an F2 population consisting of 203 individuals. The map was generated using the JoinMap software (version 4.0) and the linkage groups were formed and ordered using a LOD score of 3.0 and maximum of 40% recombination. The genetic map consisted of 12 major and four minor linkage groups covering a total genome distance of 2547.5 cM with an average distance of 14.25 cM between markers. Of the 152 pairs of microsatellite markers available for Capsicum annuum, 62 were successfully transferred to C. baccatum, generating polymorphism. Forty-two of these markers were mapped, allowing the introduction of C. baccatum in synteny studies with other species of the genus Capsicum.
Assuntos
Capsicum/genética , Genoma de Planta , Repetições de Microssatélites , Locos de Características Quantitativas , Alelos , Mapeamento Cromossômico , Marcadores Genéticos , Escore Lod , Polimorfismo Genético , Polimorfismo de Fragmento de RestriçãoRESUMO
Genetic mapping is very useful for dissecting complex agronomic traits. Genetic mapping allows for identification of quantitative trait loci (QTL), provide knowledge on a gene position and its adjacent region, and enable prediction of evolutionary mechanisms, in addition to contributing to synteny studies. The aim of this study was to predict genetic values associated with different agronomic traits evaluated in an F2 population of Capsicum baccatum var. pendulum. Previously, a reference genetic map for C. baccatum was constructed, which included 183 markers (42 microsatellite, 85 inter-simple sequence repeat, and 56 random amplification of polymorphic DNA) arranged in 16 linkage groups. The map was used to identify QTL associated with 11 agronomic traits, including plant height, crown diameter, number of days to flowering, days to fruiting, number of fruits per plant, average fruit weight, fruit length, fruit diameter, fruit pulp thickness, soluble solids, and fruit dry weight. QTL mapping was performed by standard interval mapping. The number of small QTL effects ranged from 3-11, with a total of 61 QTL detected in 9 linkage groups. This is the first report involving QTL analysis for C. baccatum species.
Assuntos
Capsicum/genética , Capsicum/classificação , Cromossomos de Plantas , Produtos Agrícolas/classificação , Produtos Agrícolas/genética , Cruzamentos Genéticos , Estudos de Associação Genética , Ligação Genética , Locos de Características QuantitativasRESUMO
Several plant organs contain proteinase inhibitors, which are produced during normal plant development or are induced upon pathogen attack to suppress the enzymatic activity of phytopathogenic microorganisms. In this study, we examined the presence of proteinase inhibitors, specifically trypsin inhibitors, in the leaf extract of Capsicum baccatum var. pendulum inoculated with PepYMV (Pepper yellow mosaic virus). Leaf extract from plants with the accession number UENF 1624, which is resistant to PepYMV, was collected at 7 different times (0, 24, 48, 72, 96, 120, and 144 h). Seedlings inoculated with PepYMV and control seedlings were grown in a growth chamber. Protein extract from leaf samples was partially purified by reversed-phase chromatography using a C2/C18 column. Residual trypsin activity was assayed to detect inhibitors followed by Tricine-SDS-PAGE analysis to determine the N-terminal peptide sequence. Based on trypsin inhibitor assays, trypsin inhibitors are likely constitutively synthesized in C. baccatum var. pendulum leaf tissue. These inhibitors are likely a defense mechanism for the C. baccatum var. pendulum- PepYMV pathosystem.
Assuntos
Capsicum/virologia , Resistência à Doença/imunologia , Vírus do Mosaico/fisiologia , Doenças das Plantas/imunologia , Doenças das Plantas/virologia , Folhas de Planta/virologia , Inibidores da Tripsina/metabolismo , Sequência de Aminoácidos , Capsicum/imunologia , Cromatografia de Fase Reversa , Eletroforese em Gel de Poliacrilamida , Dados de Sequência Molecular , Extratos Vegetais/metabolismo , Inibidores da Tripsina/químicaRESUMO
Capsicum species are frequently described in terms of genetic divergence, considering morphological, agronomic, and molecular databases. However, descriptions of genetic differences based on anatomical characters are rare. We examined the anatomy and the micromorphology of vegetative and reproductive organs of several Capsicum species. Four Capsicum accessions representing the species C. annuum var. annuum, C. baccatum var. pendulum, C. chinense, and C. frutescens were cultivated in a greenhouse; leaves, fruits and seeds were sampled and their organ structure analyzed by light and scanning electronic microscopy. Molecular accession characterization was made using ISSR markers. Polymorphism was observed among tector trichomes and also in fruit color and shape. High variability among accessions was detected by ISSR markers. Despite the species studied present a wide morphological and molecular variability that was not reflected by anatomical features.